1. Field of the Invention
This invention relates generally to processes for peeling fresh citrus fruit and, more particularly, to such processes that utilize the infusion of a pectinase enzyme into the peel of the fruit.
2. Description of the Related Art
An example of a pectinase enzyme-infusion process of this particular kind is described in U.S. Pat. No. 4,284,651 to Bruemmer. In the described process, washed citrus fruit such as oranges and grapefruit are initially heated to a surface temperature of about 40 to 60 degrees C. and a core temperature of about 20 to 40 degrees C., after which the peel surface of the fruit is scored so as to penetrate the fruit's albedo or white layer, but not penetrate the fruit's juice segments. An aqueous solution of a pectinase enzyme is then vacuum infused into the fruit's albedo, at a vacuum of about 25 to 30 inches of mercury. After incubating the fruit for a period of 15 minutes to 2 hours, at a temperature of about 30 to 60 degrees C., maintained by application of external heat, the peel and other membrane material are removed from the fruit and the exposed fruit segments are separated from each other, with most of the segment membranes remaining intact. The fruit segments can then be refrigerated for extended durations, while substantially retaining a fresh fruit flavor and appearance.
The process described briefly above has proven to be generally satisfactory in providing individual fruit segments having a substantially fresh fruit flavor and appearance. There is a need, however, for a process whereby fruit remains whole during the peeling process rather than tending to become segmented. Maintenance of the fruit in a whole state during the peeling process facilitates more rapid removal of the peel and permits mechanization of the process. In addition, such peeled whole fruit can be attractively packaged and sold for applications, such as "cartwheel" (i.e., transverse) slicing, to which segmented fruit does not readily lend itself. Peeled whole fruit also eliminates the problem of the loss of separated segments that are damaged and/or carry adhered albedo. The process described briefly above--which clearly appears to have been designed specifically to produce fruit segments--has not been satisfactory in reliably providing such peeled whole fruit.
It should, therefore, be appreciated that there is a need for an improved process for enzyme peeling fresh citrus fruit, which is effective in providing peeled whole fruit, with ease in peeling and little adhering albedo. The present invention fulfills this need.